Commit Message

Upstream always forced _FORTIFY_SOURCE=2. At first, I tried changing
their flags to undefine that macro first, but that did not work well.
This patch ensures that the package always respects our toolchain
settings, even in cases where we are not fortifying the build.
This fixes a build failure where the mmc-utils package failed to build
with, e.g., BR2_FORTIFY_SOURCE_1:
<command-line>:0:0: error: "_FORTIFY_SOURCE" redefined [-Werror]
<command-line>:0:0: note: this is the location of the previous definition
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
---
...on-the-build-env-for-_FORTIFY_SOURCE.patch | 27 +++++++++++++++++++
1 file changed, 27 insertions(+)
create mode 100644 package/mmc-utils/0001-Rely-on-the-build-env-for-_FORTIFY_SOURCE.patch

Hello,
On Tue, 7 Aug 2018 17:32:51 +0200, Jan Kundrát wrote:
> Upstream always forced _FORTIFY_SOURCE=2. At first, I tried changing> their flags to undefine that macro first, but that did not work well.> This patch ensures that the package always respects our toolchain> settings, even in cases where we are not fortifying the build.> > This fixes a build failure where the mmc-utils package failed to build> with, e.g., BR2_FORTIFY_SOURCE_1:> > <command-line>:0:0: error: "_FORTIFY_SOURCE" redefined [-Werror]> <command-line>:0:0: note: this is the location of the previous definition> > Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Is this fixing a build issue reported by the autobuilders ? Or only
with hardening options ? Your commit log is not very verbose in details
about the configuration/condition under which the build failure happens.
Thanks!
Thomas

All,
On Wed, Aug 8, 2018 at 8:17 AM Thomas Petazzoni
<thomas.petazzoni@bootlin.com> wrote:
>> Hello,>> On Tue, 7 Aug 2018 17:32:51 +0200, Jan Kundrát wrote:> > Upstream always forced _FORTIFY_SOURCE=2. At first, I tried changing> > their flags to undefine that macro first, but that did not work well.> > This patch ensures that the package always respects our toolchain> > settings, even in cases where we are not fortifying the build.> >> > This fixes a build failure where the mmc-utils package failed to build> > with, e.g., BR2_FORTIFY_SOURCE_1:> >> > <command-line>:0:0: error: "_FORTIFY_SOURCE" redefined [-Werror]> > <command-line>:0:0: note: this is the location of the previous definition> >> > Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>>> Is this fixing a build issue reported by the autobuilders ? Or only> with hardening options ? Your commit log is not very verbose in details> about the configuration/condition under which the build failure happens.
(I haven't directly talked with Jan on this) It looks very similar to
other pkgs him and I looked at where flags were messy in the pkg and
now exposed when a build is done using hardening options, not a
autobuilder.
This isn't related to my hardening fixes patchset (ie those patches
won't fix this issue). Instead, I'd refactor this patch to move the
AM_CFLAGS "-D_FORTIFY_SOURCE=2" into the CFLAGS ?= . That should be
an upstream-able change and preserve their intent.
Matt

On pátek 10. srpna 2018 4:56:39 CEST, Matthew Weber wrote:
> This isn't related to my hardening fixes patchset (ie those patches> won't fix this issue). Instead, I'd refactor this patch to move the> AM_CFLAGS "-D_FORTIFY_SOURCE=2" into the CFLAGS ?= . That should be> an upstream-able change and preserve their intent.
Hi Matthew,
doing just this change, as you suggested:
-AM_CFLAGS = -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2
-CFLAGS ?= -g -O2
+AM_CFLAGS = -D_FILE_OFFSET_BITS=64
+CFLAGS ?= -g -O2 -D_FORTIFY_SOURCE=2
...stil results in an error when building this manually out-of-box, outside
of Buildroot, on a Gentoo Linux with hardened GCC which enforces
_FORTIFY_SOURCE via compiler spec files. The good news is that it is now
possible to override the CFLAGS via an env var when invoking make. I guess
I'll send this upstream, then.
It still doesn't work out-of-box everyhere, but it is no longer a Buildroot
bug (and it will work in Buildroot).
With kind regards,
Jan

Jan,
On Thu, Oct 25, 2018 at 1:03 PM Jan Kundrát <jan.kundrat@cesnet.cz> wrote:
>> On pátek 10. srpna 2018 4:56:39 CEST, Matthew Weber wrote:> > This isn't related to my hardening fixes patchset (ie those patches> > won't fix this issue). Instead, I'd refactor this patch to move the> > AM_CFLAGS "-D_FORTIFY_SOURCE=2" into the CFLAGS ?= . That should be> > an upstream-able change and preserve their intent.>> Hi Matthew,> doing just this change, as you suggested:>> -AM_CFLAGS = -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2> -CFLAGS ?= -g -O2> +AM_CFLAGS = -D_FILE_OFFSET_BITS=64> +CFLAGS ?= -g -O2 -D_FORTIFY_SOURCE=2>> ...stil results in an error when building this manually out-of-box, outside> of Buildroot, on a Gentoo Linux with hardened GCC which enforces> _FORTIFY_SOURCE via compiler spec files. The good news is that it is now> possible to override the CFLAGS via an env var when invoking make. I guess> I'll send this upstream, then.>> It still doesn't work out-of-box everyhere, but it is no longer a Buildroot> bug (and it will work in Buildroot).
Good to note.
Wasn't sure if you saw the merge of the updated hardening feature set.
It is now handled in the toolchain wrapper and more packages (without
changes directly in the package to allow flags to be set) should build
with the hardening flags. The wrapper appends them to the compiler
args transparently and doesn't depend on ?=.
Matt